Figure 2.

A set of typical experimental temporal profiles of a source detector pair without and with an absorbing object. Curves a, b, and c correspond with the location of absorber at a, b, and c in Fig. 1, respectively. Curve marked uniform was the temporal profile without absorber. The source and the detector were located at the central line of the square on the opposite sides. [Reprinted with permission from ref. 9 (Copyright 1996, Optical Society of America).]